On mobile devices, failure to allocate from a CMA area constitutes a functional failure. Sometimes during CMA allocations, we have observed that pages in a CMA area allocated through alloc_pages(), that we're trying to migrate away to make room for a CMA allocation, are temporarily pinned. This temporary pinning can occur when a process that owns the pinned page is being forked (the example is explained further in the commit text), or it is exiting. This patch addresses this issue by indefinitely retrying allocations that fail due to a return of -EBUSY. Change log: v1: We were performing retries of the allocation a fixed number of times. Andrew Morton disliked this, as it didn't guarantee that the allocation would succeed. v2: To address this concern, we switched to retrying indefinitely, as opposed to doing to retrying the allocation a limited number of times. Chris Goldsworthy (1): mm: cma: indefinitely retry allocations in cma_alloc mm/cma.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
